I have a slightly different thought. I am inclined to not allow any advertisements for products by a new member (new member being defined as in the conga lines). There have been recent spams by brand new members that were just unwanted (and sneaky). However, some of these might show up in another member's thread, which is something you, as the reader, would just have to ignore.
I just don't see the regulars as being a problem. And we do have a Buy/Sell/Trade forum for these very threads.